Benzo(f)quinoline has been recommended for study in the NTP as a mutagenic air pollutant and as a representative of nitrogen-containing aromatic heterocyclic compounds. It is present in various crude oils. Preliminary studies indicate that it may have carcinogenic potential. Before being tested in the bioassay program, disposition studies are needed to assess its absorption, distribution, metabolism and excretion. Such studies will not only result in more appropriate dose settings for toxicity studies, but a better understanding of the mechanism of toxicity of this compound.